Calgary police are asking for the public's help in investigating a sexual assault that took place early Sunday morning.

Police say a female was walking in the area of 36th Street N.E. between 24th Avenue N.E. and Rundlehorn Drive N.E. when a male approached her on foot and attempted to talk to her. The female was then forced into a nearby vestibule where she was threatened and sexually assaulted.

The suspect is described as a dark skinned male, roughly 18- to 25-years-old and between five feet, eight inches and six feet tall.

He is described as heavy set, dark hair and was wearing a flat brimmed black and silver sports hat.

He also wore a New Orleans Saints jersey with the number 25 on it, a large silver chain around his neck, a black winter jacket with a red liner, white runners with the tongue sticking out and dark, baggy jeans.

Anyone with information about the incident is asked to call police or Crime Stoppers.